【简答题】SECTION A COMPOSITION (35 MIN) Some say it is human nature to want something new and something different. Comment on this. Write on ANSWER SHEET TWO a composition of about 200 words on the following t...
【单选题】关于右图DNA分子片段的说法正确的是 ( ) A .限制性内切酶可作用于1部位,解旋酶作用于3部位 B .2处的碱基缺失导致染色体结构的变异 C .把此DNA放在含15N的培养液中复 制2代,子代中含15N的DNA占3/4 D .该DNA的特异性表现在碱基种类和(A+T)/(G+C)的比例上